DOC add the Random Kitchen Sink synonym to the RBFSampler section

This should make it easier for people to find this code if they search for the
terms 'random kitchen sink' and 'python'.
Merge pull request #3297 from esc/doc/random_kitchen_sink

DOC add the Random Kitchen Sink synonym to the RBFSampler section
MAINT reduce amount of boiler code using standard C operations
DOC give example of binarizing binary targets

H/T @ilam